All-optical Quantum Devices Based On Three-mode Optomechanical Systems

With the development of nano and ground-state cooling technologies,the optomechanical system is constantly getting smaller and smaller,and the quantum effects therein are also becoming more and more apparent,so this provides a promising platform for exploring and testing quantum theories in meso-or even macroscopic scales.With such progress,optomechanics has made lots of significant breakthroughs including non-classical state preparation,quantum information processing,and further quantum internet.On one hand,optomechanical systems are of strong nonlinearities which lead to abundant novel phenomena and important applications in both classical and quantum regimes,because couplings between optical and mechanical modes are essentially nonlinear.On the other hand,when the control field of the optomechanical system is strong enough,the optomechanical coupling can be linearized.In this regime,one can realize a lot of important applications,such as optomechanically induced transparency(OMIT),optical non-reciprocity,mechanical ground-state cooling,and precise measurement.In particular,OMIT and relevant quantum coherent effects play key roles for realizing all-optical switching,fast and slow light,and light storage.Recently,studies of such phenomena have been extended from conventional passive optomechanical systems to active-passive ones.It has been proved that the latter may provide more optimized and more abundant quantum coherent phenomena.In this dissertation,we improve the existing conventional three-mode optomechanical system and study the steady-state optical response of the weak probe field.Compared with the previous works,we consider here two improvement schemes:(i)to consider the right cavity to be active,and the gain therein is balanced with the loss of the left passive cavity,here,both cavities are driven by a red-sideband control field,respectively;(ii)to consider both cavities are passive,which are driven by red-and blue-sideband control fields,respectively.With the first scheme,we consider first that only the left passive cavity is probed by a weak signal.It shows that by adjusting the strength of the control field,one can control the ratio between the intensities of the two output fields and even realize oneway output phenomenon.Due to the introduction of the gain,both output fields can be amplified within a certain range of parameters.Moreover,we observe an absorption-amplification transition of the probe fields accompanied with a fast-slow light transition.Then,we consider that there are two probe fields incident from the left and right cavities,respectively,and assume that there is a tunable phase difference between the probe fields.It shows that the optical response is significantly sensitive to both the strength of the control field and the phase difference between the probe fields.With certain parameters,one can observe a novel quantum coherent phenomenon called frequencyindependent perfect reflection.Such a phenomenon is independent of probe frequency and thereby can be used for realizing perfect reflector of wide-frequency light.With the second scheme,we assume that the frequencies of the two probe fields are different,instead they meet a certain matching condition.With this model,we observe ultra-narrow response windows which can be used for realizing some important applications,such as precise sensing and accurate amplification.If the two control fields are in phase,one can realize coherent perfect absorption with ultra-narrow window,while if they are out of phase,significant optical amplification can be observed.The resulting amplification here is much stronger than that of the three-mode optomechanical system driven by monochromatic control fields.Moreover,we also study the slow light effect in the amplification regime.